Hobbyists may have provided the first demand for 3-D printing, but while DIY enthusiasts were creating online communities to make their own action figures and knickknacks out of plastic, industrial manufacturers were discovering how new materials and techniques in 3-D printing could change the way they make commercial products.

A 3-D printer deposits a string of hot plastic, lets it cool, and moves on to the next plane to build a three-dimensional object slice by slice. Using the same principles of layering, additive manufacturing can build objects out of metals, plastics, and ceramics in geometric shapes that are impossible to achieve with other manufacturing techniques. Because the design is digital, businesses can order the resulting products from any available 3-D printer.

This May, General Electric announced that it would intensify its focus on additive manufacturing to develop a variety of products, from aircraft engine components to parts for ultrasound machines. Other large manufacturers have used the technique to make industrial scanners, furniture, and medical equipment.

Bart Van der Schueren, executive vice president of Materialise, an additive-manufacturing company based in Belgium, credits advances in chemistry and printing processes with opening up additive manufacturing beyond prototypes. In stereolithography, for example, a laser moves slice by slice through a vessel of liquid polymer that hardens when struck by the beam. This enables printers to create smooth and detailed surfaces.

More than 100 companies worldwide do some sort of 3-D additive manufacturing, according to industry analyst Wohlers Associates. However, many companies are still offering only prototype services. Additive manufacturing also has limits: it can’t be used to make products over a certain size, it doesn’t work with all materials, and it can’t be easily used to make an object out of more than one material.

But because additive manufacturing requires no assembly and can turn a mere a computer file into products made to exact specifications, it can open up opportunities for entrepreneurs. CloudFab, a San Francisco-based startup founded in 2009, offers consumers and entrepreneurs design software and a network of 3-D printers to make their products. The user uploads the design, and for a commission, CloudFab delegates orders to its printing partners.

CloudFab founder Nick Pinkston says the company has seen a 10 percent increase in orders each month since its founding; it has processed 20,000 orders to date. “The digital-manufacturing movement, and the ability for [individuals] to make products and bring them to market, is a big thing,” he says. “Our whole goal is to make product designers and industrial designers the new Web designers.”